Napa weather by month
What a typical year looks like in Napa, California: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at NAPA STATE HOSPITAL, 4 km from Napa; records cover 1893–2026.
The year at a glance
- Precipitation a year
- 26.7 in677 mm
- Snow a year
- Rare
- Last spring freeze
- Feb 9
- First fall freeze
- Dec 4
- Heating degree days
- 2,357
- Cooling degree days
- 640
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 30°−1° (heating, 99%) and 100°38° (cooling, 1%).
Month by month
Napa in January
Highs average 59°15° and lows 40°5°, with 5 in126 mm of precipitation in a typical January.
- Record high
- 85°29° (1962)
- Record low
- 19°−7° (1937)
- Heating degree days
- 485
- Cooling degree days
- 0
Napa in February
Highs average 63°17° and lows 42°5°, with 5.1 in130 mm of precipitation in a typical February.
- Record high
- 86°30° (1899)
- Record low
- 23°−5° (1917)
- Heating degree days
- 349
- Cooling degree days
- 0
Napa in March
Highs average 68°20° and lows 44°6°, with 3.7 in93 mm of precipitation in a typical March.
- Record high
- 92°33° (1914)
- Record low
- 23°−5° (1949)
- Heating degree days
- 295
- Cooling degree days
- 2
Napa in April
Highs average 72°22° and lows 46°8°, with 1.7 in44 mm of precipitation in a typical April.
- Record high
- 95°35° (1921)
- Record low
- 27°−3° (1929)
- Heating degree days
- 197
- Cooling degree days
- 12
Napa in May
Highs average 77°25° and lows 50°10°, with 1.1 in27 mm of precipitation in a typical May.
- Record high
- 104°40° (1910)
- Record low
- 30°−1° (1974)
- Heating degree days
- 99
- Cooling degree days
- 44
Napa in June
Highs average 82°28° and lows 54°12°, with 0.29 in7.4 mm of precipitation in a typical June.
- Record high
- 113°45° (1961)
- Record low
- 34°1° (1929)
- Heating degree days
- 22
- Cooling degree days
- 112
Napa in July
Highs average 83°29° and lows 56°13°, with 0 in0 mm of precipitation in a typical July.
- Record high
- 112°44° (1972)
- Record low
- 38°3° (1929)
- Heating degree days
- 5
- Cooling degree days
- 141
Napa in August
Highs average 84°29° and lows 56°13°, with 0.06 in1.5 mm of precipitation in a typical August.
- Record high
- 110°43° (1900)
- Record low
- 37°3° (1932)
- Heating degree days
- 4
- Cooling degree days
- 147
Napa in September
Highs average 84°29° and lows 53°12°, with 0.09 in2.3 mm of precipitation in a typical September.
- Record high
- 114°46° (2022)
- Record low
- 36°2° (1932)
- Heating degree days
- 14
- Cooling degree days
- 131
Napa in OctoberThis month
Highs average 78°26° and lows 49°10°, with 1.3 in34 mm of precipitation in a typical October.
- Record high
- 106°41° (1980)
- Record low
- 28°−2° (1946)
- Heating degree days
- 89
- Cooling degree days
- 49
Napa in November
Highs average 66°19° and lows 44°6°, with 2.8 in70 mm of precipitation in a typical November.
- Record high
- 90°32° (1895)
- Record low
- 25°−4° (1928)
- Heating degree days
- 305
- Cooling degree days
- 2
Napa in December
Highs average 59°15° and lows 40°4°, with 5.5 in140 mm of precipitation in a typical December.
- Record high
- 81°27° (1967)
- Record low
- 14°−10° (1990)
- Heating degree days
- 493
- Cooling degree days
- 0